This invention relates generally to medical devices and, more particularly, to retention bolsters for adjustably supporting a tubular medical device adjacent an epidermal surface.
Typically, a retention bolster is positioned at the exit site of a catheter to hold the catheter securely against the patient's body. The bolster is locked in place to maintain support of the catheter and prevent bending or crimping of the catheter at the exit site. So positioned, bolsters apply continual, direct pressure to the skin at the exit site of the catheter from the patient's body, sometimes having the effect of inhibiting the healing of the skin at the exit site of the catheter and possibly causing necrosis due to the applied pressure.
Bolsters for supporting tubular medical devices, such as catheters, outside the body have generally focused on maintaining the secure anchoring of the device to the patient. To provide lateral support, bolsters have employed flanges, cross-bars, or discs for contacting the epidermal surface. Prior attempts at minimizing the continual, direct pressure applied by these supports have included the placement of pads or webs underneath the cross-bars, for example, of the bolster. Pads and webs, however, have actually tended to increase the localized pressure at the exit site, especially when the catheter, either accidentally or intentionally, is moved thereabout. Further, as percutaneous catheter placement techniques have become increasingly common, catheters have been increasingly used for longer periods of time. As such, infections of the skin at the catheter exit site have become increasingly common as well.
One particular application magnifying the deficiencies of existing bolsters involves the use of percutaneous gastrostomy catheters (PEG tubes) to provide long term access into the stomach. A PEG tube is maintained at its stoma exit site by a retention bolster for several months while it is used to provide access into the stomach. Existing bolsters, however, which remain inflexibly clamped to maintain the catheter in position during use, do not accommodate the unavoidable movements of the catheter during this long period of time. As the catheter is moved about, either accidentally or as it is handled by attending medical personnel, additional pressure is often applied causing the bolster to dig into the skin surface and resulting in pressure sores and maceration of the stoma site. As a result of these deficiencies, existing bolsters have often been the source of irritation and infections of the skin.
A need, therefore, has existed for an improved retention bolster for use adjacent an epidermal surface to support a tubular medical device. Such a bolster, which securely holds a catheter in place while exerting minimal amounts of pressure at the catheter exit site, and permits movement of the catheter about the stoma exit site without causing or aggravating injury thereat, has been disclosed and claimed in the above co-pending application Ser. No. 07/911,171.
Most of the catheters used in long term enteral feeding are made from inert, biocompatible medical grade silicone rubber or polyurethane. These catheters are soft, flexible and are comfortable for the patient. One problem with these catheters has been their tendency to kink at the point where the catheter is flexed over at a right angle, which is often done when the catheter is taped down on the skin surface. Repeated flexing of the catheter at the juncture as it exits the bolster creates continuous stress at that flexure point, such that it weakens the catheter and creates stress fractures and cracking of the catheter wall leading to premature failure of the medical device. This is especially true in smaller diameter size catheters typically 18 Fr. in size or smaller used in pediatric patients. These smaller size catheters have thinner wall thicknesses which makes them even more susceptible to premature failure from repeated flexing of the tube.